Can't access IE after installing spyware

I posted this in software, but I wasn't sure which category it belongs in. I know next to nothing about computer, so I apologize if I come off ignorant.
I forgot to mention my OS is Windows XP

Someone please help. I was following instructions on this site regarding installing spyware and adware removers. I turned the Systems Restore option off as advised, and went to that screen where you select reboot options. I chose safe mode with networking, but when I logged on as admin, no icons were visible, no start menu, and I can't right click with my mouse. I restarted in normal mode, but there is still nothing.
I can open most applications in Task Manager, but when I try to open Internet explorer, it says it doesn't exist.
Dell support wants to charge me $80 bucks to help me fix this problem, and I just can't afford it. I'm supposed to start college in two weeks, and I need my computer for school, so I would REALLY appreciate any assistance.

Thank you in advance

 

When I tried to do that, I got this error message:


Windows cannon find 'c:\windows\explorer.exe'. Make sure you typed the name correctly and then try again. To search for a file, click the Start button and then click Search.


My comp is a Dell Optiplex 4600. I don't know the specs. I don't even know what specs are. I've been browsing the forums trying to educate myself, but I'm way over my head here.

 

Ok, I pulled up the C drive. No i386. I looked in the Windows folder too and it's not there either. How do I find out what version of XP I'm running?
(I thought I knew something about computers, but I guess not) Thank you for your help.

 

I did a little research, and I guess SP stands for Service Pack? I didn't install any service packs, so I guess it's just regular XP.

I think I'm just going to reinstall the OS. I have directions I printed out and I'll give it a try.

 

Ok, well after rooting around in my computer last night, I found out I am running XP SP2. I found i386 in a Driver Cache folder deep in the interior jungle of my computer. I'm not sure I could find it again if I tried.
I have a feeling I know what I did. After downloading the recommended spyware removers from this site, I ran Adaware SE, Spybot and another Spy.... I believe one of these quarantined a file vital to my Operating System, and I purged the damn thing because I didn't know enough about computers to be performing these functions anyway! I thought these programs knew helpful files from non-helpful. How foolish.
A computer support person at work suggested I try to replace the explorer.exe in the correct file and see if this fixes this problem.
I have already tried to reformat and repair install from my Windows XP cd, but an error message popped up saying the version on the cd was older than that on my computer and it couldn't boot. I'm figuring that's because I'm running XP SP2 and the cd is only XP, right?
My father-in-law is driving me nuts. He's telling everyone Dell sent a virus to destroy my computer. That's crap, isn't it? He wants to fix my computer, but he doesn't even know what downloading is!!
Is there anywhere I can teach myself more about computers, how they operate and how to troubleshoot them? I don't even know what these HiJack This logs everyone on this site talks about are.
Thank you for you help.